Multi-Link Channel Contention After CCA Blindness Periods
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Solution Overview
Problem
Non-simultaneous transmit and receive multi-link devices experience channel interference and inter-frame collisions due to blindness periods, leading to inefficient communication.
Innovation Solution
Implement a channel contention method where a non-access point station performs clear channel assessment (CCA) on a second link after completing data transmission on a first link, adjusting CCA thresholds and using an extended time period to avoid collisions and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a non-STR multi-link device performs data transmission on one link, then data transmission is achieved, but channel interference affects CCA on another link causing blindness period
Solution Approach 1:
The patent applies preliminary action by performing CCA detection on the second link during the first time period, which starts at the moment data transmission on the first link is completed. This提前 detection allows the device to identify channel status before attempting channel contention, preventing the blindness period from causing missed detection opportunities. The medium sync delay timer is used to schedule this preliminary CCA detection before the second link's CCA opportunity.
Solution Approach 2:
The patent segments the channel access process into distinct time periods: a first time period for CCA detection after data transmission completes, and a second time period for channel contention. This segmentation allows the device to separately handle detection and contention phases, ensuring that CCA is performed at the appropriate time without interference from ongoing transmissions on other links.
2Reliability
If the device performs CCA detection after data transmission completes, then channel status can be monitored, but inter-frame collision occurs with ACK frames
Solution Approach 1:
The patent performs CCA detection in advance during the first time period, before the ACK frame transmission opportunity arises. By detecting channel status early and using the medium sync delay timer to control the timing, the device can identify whether the channel is busy before attempting to transmit, thereby avoiding inter-frame collisions with subsequent ACK frames.
Solution Approach 2:
The patent uses feedback from CCA detection results to determine whether to proceed with channel contention. If CCA detection indicates the channel is busy (detecting an ACK frame or other transmissions), the device adjusts its channel access timing accordingly, preventing collisions by feedback-based decision making.
3Productivity
If the device accesses the channel immediately after OBSS frame transmission ends, then channel utilization is improved, but collision with ACK frame occurs
Solution Approach 1:
The patent performs preliminary CCA detection during the first time period to determine channel status before attempting immediate access. This preliminary check ensures that the device only accesses the channel when it is truly idle, maintaining high utilization while avoiding collisions with ACK frames that may follow OBSS transmissions.
Solution Approach 2:
The patent changes the timing parameters of channel access by introducing the medium sync delay timer and distinguishing between a first time period for CCA and a second time period for contention. This parameter adjustment allows the device to optimize channel utilization while maintaining reliability by accessing the channel at the optimal moment.
Data Source
AI summary
This application provides a channel contention method and a related apparatus. The method includes: After data transmission on a first link is completed or a block acknowledgment corresponding to data is received on the first link, a first non-access point station of a first multi-link device performs clear channel assessment CCA detection on a second link in a first time period, where a start moment corresponding to the first time period is the same as a moment at which the data transmission on the first link is completed; and when the CCA detection on the second link fails, the first non-access point station performs channel contention on the second link based on a second time period.